.main {
  position: relative;

  .maincenter {
    margin: 20px;
    display: flex;
    justify-content: space-around;
  }

  .mask {
    width: 90vw;
    height: 500px;
    background: rgba($color: #000000, $alpha: 0);
    position: absolute;
    top: 490px;
    left: -50px;
    z-index: 20;
  }
}